> ## Documentation Index
> Fetch the complete documentation index at: https://docs.photon.codes/docs/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Use Stable documentation by default. Honor an explicit Beta request or a URL under /docs/beta/. If the requested version conflicts with the installed CLI package or API origin, clarify the target before writing integration code.
> Pages under /docs/beta/ document Beta; other product pages document Stable. Keep the CLI package, commands, API origin, and credentials within the selected version. State the documentation version in your answer.
> For MCP search, always pass version: Stable or version: Beta. Unfiltered search mixes both versions. For filesystem reads, keep Beta queries under /beta/ and exclude /beta/ from Stable queries; discover paths before reading them.
> The public docs base is https://photon.codes/docs. Convert MCP page paths to public URLs under that base, preserving /beta/ when present. Read https://photon.codes/docs/skill.md for version selection and https://photon.codes/docs/llms.txt for the version indexes.

# MentionHandler

> Handler for new @-mentions of the bot.

**Important**: This handler is ONLY called for mentions in **unsubscribed** threads.
Once a thread is subscribed (via `thread.subscribe()`), subsequent messages
including @-mentions go to `onSubscribedMessage` handlers instead.

To detect mentions in subscribed threads, check `message.isMention`:

```typescript
// Handle new mentions (unsubscribed threads only)
chat.onNewMention(async (thread, message) => {
  await thread.subscribe();  // Subscribe to follow-up messages
  await thread.post("Hello! I'll be watching this thread.");
});

// Handle all messages in subscribed threads
chat.onSubscribedMessage(async (thread, message) => {
  if (message.isMention) {
    // User @-mentioned us in a thread we're already watching
    await thread.post("You mentioned me again!");
  }
});
```

```typescript
type MentionHandler = (thread: Thread<TState>, message: Message, context: MessageContext) => void | Promise<void>
```


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